1. Field of the Invention
This invention relates generaly to dispensers for viscous material, and more particularly to a system or apparatus for delivering and guiding a paste from a flexible storage container accommodated in a dimensionally stable container ("pot") downwards into a dispenser operating by reduced pressure.
2. Discussion of Related Art
Liquid to paste-form detergents are well known in the prior art. They are generally formulated to meet domestic requirements, i.e. they are expected to be sufficiently liquid so that they can be poured out and measured/dosed without difficulty. Since, in addition, they are expected to be stable in storage over a relatively broad temperature range, the use of organic solvents and/or hydrotropic additives cannot normally be avoided. However, such additives do not contribute to the actual washing process, are comparatively expensive and, in addition, take up packaging space and transportation and storage capacity. The presence of inflammable solvents is particularly troublesome and necessitates additional safety precautions on account of the relatively high consumption of detergents in laundries. Because of this, detergent concentrates of the type mentioned can only be used to a limited extent, if at all, in laundries.
Accordingly, powder-form detergents are mainly used in laundries. Since the exact dosing of powder-form detergents is problematical or labor-intensive, particularly in large and extensively automated laundries, the detergents are mostly stored and dispensed in predissolved form as stock liquors, i.e. a water-based concentrate is prepared and delivered to the individual points of consumption. However, the detergents typically used in laundries contain comparatively high levels of washing alkalis which are only soluble to a limited extent in cold water and, lead to so called salting-out effects. They promote phase separation with the result that the organic components, more especially the nonionic surfactants and soaps, separate and cream up. Accordingly, the concentrates have to be diluted relatively heavily with water and, in addition, the stock liquors have to be constantly and intensively mixed and circulated to prevent individual components being deposited in the feed lines to the points of consumption. Processes such as these require considerable investment in large mixing vessels and the associated static mixers and feeders, and also require a constant supply of energy for the heating and circulation of the stock liquors.
A detergent which meets these requirements is proposed in EP 0 295 525. This detergent is a paste which imposes particular demands on handling for the purpose of dosing and mixing with water as solvent. Detergent pastes such as these are transported and stored in large containers.